Tap Water Quality Report
Tap water quality in GREENWICH, Connecticut
Tap water in GREENWICH, Connecticut receives a grade of F (59/100) from TapWaterSafety.org. It's served by 3 public water systems, primarily AQUARION-GREENWICH. The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; PFAS contamination. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in GREENWICH's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utilities serving GREENWICH.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 52.5 ppb, 874x above the EWG health guideline of 0.06 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 38.9 ppb, 389x above the EWG health guideline of 0.1 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 49.5 ppb, 330x above the EWG health guideline of 0.15 ppb.
PFAS contamination
Severe concernPerfluorooctane sulfonate (PFOS), Perfluorooctanoic acid (PFOA) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Water systems serving GREENWICH
GREENWICH is served by 3 public water systems. Click any utility to see its complete grade card and treatment plant contact info.
AQUARION-GREENWICH
- Haloacetic acids (HAA9) significantly above health guideline
- Haloacetic acids (HAA5) significantly above health guideline
- Total trihalomethanes (TTHMs) significantly above health guideline
AQUARION-STAMFORD
- Haloacetic acids (HAA9) significantly above health guideline
- Haloacetic acids (HAA5) significantly above health guideline
- Total trihalomethanes (TTHMs) significantly above health guideline
AQUARION-EASTERN FAIRFIELD COUNTY
- PFAS contamination
- Haloacetic acids (HAA9) significantly above health guideline
- Total trihalomethanes (TTHMs) significantly above health guideline
Recommended filters for GREENWICH
Filters matched to the specific contaminants in GREENWICH's water supply.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in GREENWICH's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA9) Disinfection byproduct |
58.1 ppb | 0.06 | — | — | — | — | — | 968× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
38.9 ppb | 0.1 | 60.0 | 60 | — | — | — | 389× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
52.4 ppb | 0.15 | 80.0 | 100 | — | — | — | 349× over |
| Trichloroacetic acid Disinfection byproduct |
21.5 ppb | 0.1 | — | — | — | — | — | 215× over |
| Bromodichloromethane Disinfection byproduct |
11.5 ppb | 0.06 | — | — | — | — | — | 191× over |
| Chloroform Disinfection byproduct |
37.1 ppb | 0.4 | — | — | — | — | — | 93× over |
| Dichloroacetic acid Disinfection byproduct |
17.2 ppb | 0.2 | — | — | — | — | — | 86× over |
| Dibromochloromethane Disinfection byproduct |
2.01 ppb | 0.1 | — | — | — | — | — | 20× over |
| Dibromoacetic acid Disinfection byproduct |
0.539 ppb | 0.03 | — | — | — | — | — | 18× over |
| Perfluorooctanoic acid (PFOA) PFAS |
1.66 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 18× over |
| Chlorite Disinfection byproduct |
403.6 ppb | 50.0 | 1000.0 | — | — | — | — | 8.1× over |
| Nitrate Inorganic |
0.765 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 5.5× over |
| Chromium (hexavalent) Heavy metal |
0.0833 ppb | 0.02 | — | — | — | — | — | 4.2× over |
| Nitrate and nitrite Inorganic |
0.525 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 3.7× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
0.893 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 3.0× over |
| Chlorate Disinfection byproduct |
159.2 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Bromoform Disinfection byproduct |
0.0784 ppb | 0.5 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
10.4 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Barium Heavy metal |
33.3 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
1.6 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.51 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.383 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
1.47 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
0.807 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluoropentanoic Acid (PFPeA) PFAS |
0.75 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluoroheptanoic acid (PFHPA) PFAS |
0.279 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
0.293 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.0956 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.325 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from AQUARION-GREENWICH.
General Contact
Treatment Plant
ZIP codes served
GREENWICH's public water systems serve the following ZIP codes: